On a machine tool, a door is provided on a processing chamber covering a processing section such as a main shaft chuck such that an operator can perform work such as maintenance or component exchange inside the processing chamber from the outside. In patent literature 1 below, a safety door is provided that opens and closes around a rotation axis via a hinge, with opening and closing being performed by using a handle. With this conventional art, a small door is formed in the safety door such that a workpiece can be removed and inserted. The small door is a raising and lowering door that is raised and lowered along slide rails, with opening and closing being performed by holding a handle a raising and lowering the small door. A slanted channel is provided on the safety door and the small door to prevent the work floor becoming dirty by having liquid droplets collected by passing through the channel.